Carburetor



A. BOULADE Feb. 1o, 1931.

CARBURETOR Filed March 25, 1925 2 Sheets-Sheet l M INVNTOR Feb. 1o, 1931.

A. BOULADE CARBURETOR Filed March 25, 1 925 2. Sheets-Sheet 2 Patented Febfl, 1Q31 PATENT OFFICE UNITED STATES ,ANTONIN BOUITADE, 0F LYON, FRANCE, ASSIGNOR T0 SOCIETE DU CABIBURATEUR ZENITH, 0F LYQN, FRANCE CARBUBETOR Application led March 25, 1925, Serial No. 18,196, and in France April 2, 1924.

The present invention relates broadly to carburetors, and more particularly to carburetors of the sol-called multiple Venturi type and to means for improving the eiiiciency 5" and operation thereof. 1

At the present time it is proposed to construct carburetors having a main outer -ven-v turi and one or more inner or secondary venturis for the purpose ofimparting ahi'gher Velocity to at least a portion of the air supplied to the engine served by the carburetor. By reason of the high velocity of this portion of the air, and by reason of the location of subjected to a strong cooling action dueto such velocit and-due to the vaporization of the fuel. uch secondary venturis are in very poor thermal contact with the main body of the carburetor and, therefore, do not receive any appreciable heat from the carburetor body such as the carburetor body itself receives either by reason of its proximity to the motor or by its own system of heating.

In actual operation, as the temperature of these inner or secondary venturis is decreased or lowered, they become coated or covered with ice due to the condensation of the humidity in the air. This ice not only impairs vaporization of the fuel and results in the undesirable condensation of a large portion thereof, but also clogs to a greater or lesser extent the orifices through which the fuel passes into the air stream, and also decreases the efened.

The present invention has for its objects I improvements in carburetors'of the so-called multiple Venturi type for the purpose of overcoming and obviating these difficulties and' improving the eic'iency and operation there- In the accompanying drawings there are such secondary venturi or venturis, they are fective area of the air passages so that the mixture may be disproportionally enrich-` shown,.for purposes of illustration only, cerparting eitherfrom the spirit of the inventive or the scope of my broader claims.

Figure 1 is a vertical Sectional view through a multiple Venturi carburetor in accordance with one embodiment of my invention;

Figure 2 is aview similar to Figure 1 illustrating a carburetor having a double or compound secondary venturi; v

Figure 3 is a view similar to Figure 1 illus- 60 trating a slightly different embodiment of my inventlon; v

Figure 11y is a view similar to Figure-2 illustrating a double or compound secondary venturi in a carburetor of the character shown in 55 Figure 3;

Figure 5 is a view similar to Figure 1 illustrating a carburetor `having electrical'heating means for the secondary venturi;

Figure 6 is a view similar to Figure 2 showing a double or compound secondary venturi having electrical heating means, and

Figure 7 is a view partly in section and partly in elevation illustrating another embodiment of the invention. 75.

The present invention is adapted particularly to multiple Venturi carburetors and to means for raising the temperature of at least one of the inner venturis irrespective of the temperature of the outer venturi or venturis.

In carrying out the present invention there may be provided a carburetor comprising a body 2 having an expanding air inlet 3 and provided with the usual main outer venturi 4. Disposed in coaxial relationship to the outer venturi is an inner or secondary venturi 5 preferably having its outlet end disposed in or adjacent to the region of maximum depression in the outer venturi, this zone ordinarily being lslightly above the point of maximum restriction of the outer venturi. In constructions of this character, the inner venturi is substantially isolated from the main carburetor body whereby it is not materially affected thermally by the temperature of the main carburetor body. VBy reason of this location and by reason of the operation of the carburetor as set forth it is desirable to provide means for raising thel temperature of the inner venturi. In the embodiment ofthe invention illustrated in Figure 1 this is accomplished by providing a jacket 6 surrounding the inner venturi and adapted to receive a supply of a heating medium, such as heated air or exhaust gases, through a passage 7 Actual experiments have shown that a small percentage of such a heating medium may be introduced into the mixture with no harmful results, and

Eor this purpose the jacket 6 is preferably formed with an annular discharge opening 8 insuring a continuous circulation of heated gases through the jacket. `The inner venturi may be supplied with fuel, or a mixture of fuel and air, in known manner through a passage 9 feeding a chamber 10 having discharge orifices 11 through the wall of the venturi. With a construction of this character it is possible to maintain the inner venturi at any desired temperature and thereby eii'ectively prevent the formation of ice on the venturi and the consequent choking of the air and fuel passages and condensation of the fuel.

In Figure 2 there is illustrated a construction similar to that shown in Figure 1 and parts corresponding in the two figures are designated by the same reference characters having a prime affixed thereto. In the construction of Figure 2 the inner venturi 5 is double or of compound nature, comprising an auxiliary venturi 12 serving to'discharge the` fuel and air into the secondary venturi 5.

In Figure 3 there is disclosed a construction similar to that shown in Figure 1 with the exception that the inner venturi 13 is adapted to be heated by a liquid which may be supplied in any desired manner. For this purpose there is disclosed an inlet passage 14 and an outlet passage 15, insuring continuous circulation. The fuel or a mixture of fuel and air may be supplied laterally through a conduit 16 delivering into the venturi through the orices 1'2.

The construction shown in Figure 4 is similar to that shown in Figure 3 with the exception that the inner venturi is of compound construction embodying a separate venturi 18 delivering to the secondary venturi 13.

Inthe embodiment. of the invention illustrated in Figure 5 the secondary venturi 19 may have a portion thereof surrounded with mica or other insulating material 20 upon which is wound suitable resistance material- 21 adapted to receive a supply of electric current for maintaining the desired temperature conditions. Terminals 22 may lead outwardly from the coil 21 for attachment to any desired source of current. The entire coil may be enclosed within a protective covering 23. With this construction also fuel or i'uel and air may be supplied through a conduit 24 to the orifices 25.

The embodiment of the invention illustrated in Figure 6 is similar to that shown in Figure 5, diiering, however, as before (lescribed, in that the inner venturi 19 is of construction having the usual outer venturi 27 v and an inner venturi 28 having its inlet connected to an air conduit 29 which in turn receives a supply of heated air from a stove or other heating means 30. The fuel for the inner venturi may be delivered through a later ally extending passage 31 discharging through the oriices 32.

With all of the forms of the 4invention herein disclosed it is possible to raise the temperature of the inner venturi irrespective of the temperature of the outer venturi, and this constitutes an important advantage of the present invention.

I claim:

1. In a carburetor, a carbureting chamber having an expanding air inlet, an outer venturi receiving air from said inlet, an inner venturi receiving air from said inlet independently of the outer venturi and discharging into said outer venturi, and means intersecting the expanding air inlet fordellvering a heating medium directly to the walls of said inner venturi, substantially as described.

2. In a carburetor, an outer venturi, an inner venturi positioned within the outer venturi and havlng a substantially unobstructed air flow space entirely around the same, such air space being established by a relatively limited supporting area between the venturis,

tive of its operating capacity. I

4. In a carburetor, an outer venturi, an inner venturi having a limited area of, and relatively poor thermal, contact with the outer venturi, such contact being incapable of transmitting heat from the outer to the inner ve turi with suiicient rapidity to prevent decrease in the temperature of the inner venturi `When the carburetor is in operation, there being a substantially continuous annular passage between the outside of the inner and the inside of the outer venturi, and means extending entirely around and in eicient, heat conducting relationship to the inner venturi for raising the temperature of the inner venturi irrespective of'the temperature of the outer venturi, substantially as described.

5. In a carburetor, an outer venturi, a compound inner venturi having an expanding aj utage extending into the outer venturi and terminating in substantially the region of maximum depression therein, and heating means for raising the temperature of at least a` portion of the inner venturi independently of the temperature of the outer venturi, substantially as described.

6. In a carburetor, an outer' venturi; an inner venturi having a limited area of, ald relatively poor thermal, contact with the outer venturi, such contact being incapable of transmitting heat from the outer to the inner venturi with sufficient rapidity to prevent decrease in the temperature of the inner venturi when the carburetor is in operation, there being a substantially continuous annular passage between the outside of the inner and the inside of the outer venturi, and a second passage for raising the temperature of the inner venturi irrespective of the temperature of the outer venturi, said means comprising a heatin chamber cooperating With the inner venturl, substantially as described.

7. In a carburetor, an outer venturi, aninner venturi having a limited area of, and relatively poor thermal, contact with the outer venturi, such contact being incapable of transmitting heat from the outer to the inner venturi with sufficient rapidity to prevent decrease in the temperature of the inner venturi when the carburetor is in operation, there being a substantially continuous annular passage between the Voutside of the inner and the inside of the outer venturi, and means for raising the tem erature of the inner venturi irrespective o the temperature of the outer venturi, said means comprising a heating chamber cooperating with the inner venturi and surrounding at least a portion of the inner venturi, substantially as described.

In testimony hereof I have hereunto set m hand.

y ANTONIN BOULADE. 

